Re: [PATCH AUTOSEL 4.9 20/87] fs: Make splice() and tee() take into account O_NONBLOCK flag on pipes

[Sasha Levin]

On Thu, Mar 28, 2019 at 12:04:17PM -0400, Steven Rostedt wrote:
> On Thu, 28 Mar 2019 15:37:49 +0000
> Slavomir Kaslev <kaslevs@xxxxxxxxxx> wrote:
>
> > On Wed, 2019-03-27 at 14:19 -0400, Sasha Levin wrote:
> > > From: Slavomir Kaslev <kaslevs@xxxxxxxxxx>
> > >
> > > [ Upstream commit ee5e001196d1345b8fee25925ff5f1d67936081e ]
> > >
> > > The current implementation of splice() and tee() ignores O_NONBLOCK
> > > set
> > > on pipe file descriptors and checks only the SPLICE_F_NONBLOCK flag
> > > for
> > > blocking on pipe arguments.  This is inconsistent since splice()-ing
> > > from/to non-pipe file descriptors does take O_NONBLOCK into
> > > consideration.
> > >
> > > Fix this by promoting O_NONBLOCK, when set on a pipe, to
> > > SPLICE_F_NONBLOCK.
> >
> > Hey Sasha,
> >
> > I don't think that this patch should be merged to stable kernels. It's
> > more of a feature rather than a bug/regression fix and it changes how
> > splice() has been working from day one.
> >
> > Can you please drop it from the stable queues?
>
> On the other hand, it keeps stable more in sync with what mainline has.
> If someone writes new code against a stable release, and depends on
> this behavior, it's less likely to break when they run it on a newer
> kernel. Which means its less likely that Linus will revert your
> change ;-)

I'm going to drop this, I don't really want to take things which
knowingly might brake userspace.

--
Thanks,
Sasha